arch/powerpc/kernel/pmc.c

   1 /*
   2  *  arch/powerpc/kernel/pmc.c
   3  *
   4  *  Copyright (C) 2004 David Gibson, IBM Corporation.
   5  *  Includes code formerly from arch/ppc/kernel/perfmon.c:
   6  *    Author: Andy Fleming
   7  *    Copyright (c) 2004 Freescale Semiconductor, Inc
   8  *
   9  *  This program is free software; you can redistribute it and/or
  10  *  modify it under the terms of the GNU General Public License
  11  *  as published by the Free Software Foundation; either version
  12  *  2 of the License, or (at your option) any later version.
  13  */
  14
  15 #include <linux/errno.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/module.h>
  18
  19 #include <asm/processor.h>
  20 #include <asm/pmc.h>
  21
  22 #if defined(CONFIG_FSL_BOOKE) && !defined(CONFIG_E200)
  23 static void dummy_perf(struct pt_regs *regs)
  24 {
  25         unsigned int pmgc0 = mfpmr(PMRN_PMGC0);
  26
  27         pmgc0 &= ~PMGC0_PMIE;
  28         mtpmr(PMRN_PMGC0, pmgc0);
  29 }
  30 #elif defined(CONFIG_PPC64) || defined(CONFIG_6xx)
  31
  32 #ifndef MMCR0_PMAO
  33 #define MMCR0_PMAO      0
  34 #endif
  35
  36 /* Ensure exceptions are disabled */
  37 static void dummy_perf(struct pt_regs *regs)
  38 {
  39         unsigned int mmcr0 = mfspr(SPRN_MMCR0);
  40
  41         mmcr0 &= ~(MMCR0_PMXE|MMCR0_PMAO);
  42         mtspr(SPRN_MMCR0, mmcr0);
  43 }
  44 #else
  45 /* Ensure exceptions are disabled */
  46 static void dummy_perf(struct pt_regs *regs)
  47 {
  48         unsigned int mmcr0 = mfspr(SPRN_MMCR0);
  49
  50         mmcr0 &= ~(MMCR0_PMXE);
  51         mtspr(SPRN_MMCR0, mmcr0);
  52 }
  53 #endif
  54
  55 static DEFINE_SPINLOCK(pmc_owner_lock);
  56 static void *pmc_owner_caller; /* mostly for debugging */
  57 perf_irq_t perf_irq = dummy_perf;
  58
  59 int reserve_pmc_hardware(perf_irq_t new_perf_irq)
  60 {
  61         int err = 0;
  62
  63         spin_lock(&pmc_owner_lock);
  64
  65         if (pmc_owner_caller) {
  66                 printk(KERN_WARNING "reserve_pmc_hardware: "
  67                        "PMC hardware busy (reserved by caller %p)\n",
  68                        pmc_owner_caller);
  69                 err = -EBUSY;
  70                 goto out;
  71         }
  72
  73         pmc_owner_caller = __builtin_return_address(0);
  74         perf_irq = new_perf_irq ? : dummy_perf;
  75
  76  out:
  77         spin_unlock(&pmc_owner_lock);
  78         return err;
  79 }
  80 EXPORT_SYMBOL_GPL(reserve_pmc_hardware);
  81
  82 void release_pmc_hardware(void)
  83 {
  84         spin_lock(&pmc_owner_lock);
  85
  86         WARN_ON(! pmc_owner_caller);
  87
  88         pmc_owner_caller = NULL;
  89         perf_irq = dummy_perf;
  90
  91         spin_unlock(&pmc_owner_lock);
  92 }
  93 EXPORT_SYMBOL_GPL(release_pmc_hardware);
  94
  95 #ifdef CONFIG_PPC64
  96 void power4_enable_pmcs(void)
  97 {
  98         unsigned long hid0;
  99
 100         hid0 = mfspr(SPRN_HID0);
 101         hid0 |= 1UL << (63 - 20);
 102
 103         /* POWER4 requires the following sequence */
 104         asm volatile(
 105                 "sync\n"
 106                 "mtspr     %1, %0\n"
 107                 "mfspr     %0, %1\n"
 108                 "mfspr     %0, %1\n"
 109                 "mfspr     %0, %1\n"
 110                 "mfspr     %0, %1\n"
 111                 "mfspr     %0, %1\n"
 112                 "mfspr     %0, %1\n"
 113                 "isync" : "=&r" (hid0) : "i" (SPRN_HID0), "0" (hid0):
 114                 "memory");
 115 }
 116 #endif /* CONFIG_PPC64 */